This invention relates to display devices operated with a high driving voltage, such as a plasma display or an electroluminescence display, and more particularly, to improvement in the safety of such display devices.
The importance of display devices as a man-machine interface has increasingly been recognized in recent years along with the development of office automation and factory automation systems. Flat display devices, such as liquid crystal display, plasma display and electroluminescence (EL) devices are expected to play a significant role as compact flat displays of higher display quality.
Since the liquid crystal display is driven with low voltages of two to five volts, electrocution accidents do not occur. In contrast, plasma displays or ELs are driven with relatively high voltages of ninety to two-hundred fifty volts. Therefore, electrocution accidents might occur if electrodes are exposed during operation when there is damage in the panel and if operators accidentally make contact with the high voltage electrodes. To cope with such accidents, prior art panels are provided with a protection plate which is positioned in front of the display panel, so as not to be damaged easily. However, the addition of such a protection plate causes a deterioration of the resolution of the display and the display device becomes bulky.
An object of this invention is to provide a display device which is highly safe and yet has an excellent display quality.
The display device, according to this invention, comprises a display panel having electrodes for display. A conductor line is provided on the display panel in a position which does not disturb the display pattern. A low voltage source is connected to one end of the conductor line, and a driving circuit of the display panel is connected to the other end of the conductor line. The operation of the driving circuit stops when the display panel is damaged or the conductor line is broken. A stopping of the drive circuit suspends the supply of all high driving voltage, toward the electrodes for the display.